nomobmw

So far it seems like achieving the maximum acceleration performance requires a full or nearly full battery. Somewhere else on this forum I remember someone asking about methods to keep the battery at maximum charge, and I think I happened on a solution, or at least a way to pump up the battery to show off a little.

There is a crazy option on our cars, presumably used as a feature match for comparisons with a non-hybrid, which simulates gears by altering the drag of the MG2 motor. In the manual, it describes this as a hill decent feature to create more engine drag.

I discovered today while playing with this, that at various speeds, if you shift into this mode and run through the options, it will cause the motor to rev at various speeds. If the speed of the motor is right (and this can vary at different vehicle speeds) then you can achieve both cruising while at the same time charging the battery at a seemingly higher rate than just normal cruising.

I went from a half charge to one step away from "green" in a short amount of time with this but I'll need to do some more testing to see if this is actually working consistently. I also don't believe this will cause any issues with the car, but if anyone knows better, please let me know .

rominl

iTrader: (4)

if the engine rev is used to charge up the battery, i would imagine that reduces the engine output a bit (coz' some work is done to charge the battery)? or maybe gas mileage would drop?

very interesting info, would love to read more results

Stormforge

i recall reading that the hybrid battery stays at around 80% charge level, because if you fully charge or discharge the battery, you would run into the problem of the battery failing prematurely. i believe that info came from priuschat forum.

nomobmw

@Romni

Yes, this is something I was doing while cruising, not while doing the acceleration run. The intent was to fully charge the battery in preparation for some performance driving. .and I'm sure the MPG would drop as you are working the engine more. It's too bad the gs450h is too rare to have a plugin kit of some sort. I'd love to start my day with a full battery.

@Stormforge

You are correct that the battery never is fully charged or discharged from what I understand, however, this is taken into account in the battery display. When the dash screen says the battery is "full" it's actually only around 80% and the hybrid system automatically stops charging it.

The reasons for this is to ensure the maximum longevity of the battery as the NiMH battery chemistry works best this way. This is also why Toyota/Lexus hasn't made the jump to LiIon batteries regardless of them being lighter and capable of storing more power because they simply won't last nearly as long as NiMH. Toyota intends the batteries to last the "life" of the car and they seem to have done a lot of research to accomplish that.


The real reason for attempting to top off the battery this way is due to the fact that the GS450h's extreme performance can only be fully realized with a fully charged (meaning ~80%) battery because the hybrid computer will then provide maximum power from both the gas engine and the electric motor.

I surmise this is the reason why there is such differing 0-60 times for the various reviews out there. It all depends on the State of Charge ( or SoC for the prius people). I remember reading an article with a race of several cars including the GS450h, and the GS owned everyone else on the first lap, and then lagged behind as the battery drained.

Ultimately, I wish Lexus would have provided some sort of feature to ensure the battery is fully charged. . something that would endeavor to run the engine to charge the battery until it was at full charge. This wouldn't be good for MPG, but it would at least let me choose to sacrifice MPG for some fun every now and then. . If they would let me charge the battery from a wall plug at home, that would be the ultimate, because then I would have both great MPG in my daily commute (as I could get out of my neighborhood and onto the main street under electric power) and allow me to go have a nice weekend romp.

rominl

iTrader: (4)

good information there, keep them coming. i agree this would be a cool idea to "charge up" the battery for prepare for some spirited driving ahead

lucasb7

I asked the smarties on PriusChat if there was a way to force charge the battery. So, if you are at a stop you can force charge it.

What you need to do:
1. Depress brake.
2. Start car
3. Shift to drive.
4. Hit gas (they said floor) while holding down brake...

Now the car will recognize that you are trying to force charge and will purely charge the battery. As the battery has a higher SOC, the engine speed will slow down accordingly and will not over charge. They did advise however that doing this all the time could have adverse effects on battery life and of course gas mileage. But it makes the car a monster!!!!

nomobmw

Thanks Lucasb7! I'm going to try that!